There is an increasing incidence of spirochete infections occurring in both the animal and human population. For example, the increase number of cases in syphilis, Treponema pallidum, Lyme disease, Borrelia burgdorferi, and Digital Dermatitis (DD).
While first reported in Italy in 1974, the past 20 years has seen a wide-spread outbreak in a non-viral Papillomatous Digital Dermatitis (PDD) Treponeme infection in cattle throughout Europe and North America; specifically, California. PDD (also referred to as “foot warts” in cattle) has been known to cause severe lameness, body weight loss, and decreased reproductive performance in infected animals. The economic significance is tremendous. The disease situation is spreading rapidly and geographically.
PDD disease is categorized into three stages: Early, intermediate and mature PDD. In early PDD the skin-horn junction of the heel near the inter-digital cleft has a flat red lesion. Intermediated PDD is characterized by a ragged lesion and destruction of the heel horn. The mature PDD has a pronounced raised “hairy wart” appearance with advanced papillae formation.
A Treponeme, Treponema spp, is involved in the pathogenesis of the PDD disease. The disease affects every aspect of the dairy and beef industry from milk production to reproductive performance and is extremely contagious with some cases affecting 90% of a given herd. In addition to bovine PDD another ungulate, the ovine, has shown ulcerative lesions, primarily around the coronary band, which also results in severe lameness. Although the exact causative agent has not yet been identified in Contagious Ovine Digital Dermatitis (CODD), the PDD related Treponema spp has been isolated and characterized. Currently, it is not known whether or not PDD, and/or CODD can spread to additional species, such as, having an affinity for humans.
Since the effectiveness of the present methods of treatment are limited, a need exists for a specific diagnostic, a functional therapeutic and a vaccine, such as a non-whole-cell vaccine, which is effective to immunize high-risk individuals and susceptible domestic animals against Treponemes, PDD and CODD.